Liquid-fuel combustion



LIQUID FUEL COMBUSTION Filed Oct. l5, 1926 2 Sheets-Sheet INVENTOR Patented Oct. 30, 1928.

UNITED STATES WALTER. H. FREE, OF NEW' BOCHLLE, NEW YORK.

Application led October 15, 1026. Serial No. 141,789.

This invention relates to liquid `fuel combustion and has particular reference to automatically-controlled combustion systems that operate in response to certain exterior 5 conditions, such as changes in temperature for example.

The principal object of this invention is to provide a simple and efficient liquid fuel burning system which is self-controlling,

J silent and which has no moving parts.

Another object of this invention is to provide a burner adapted to utilize aheavy liquid fuel, such as the hydro-carbon liquids, which may be desirable for commercial or 5 domestic heating. The apparatus, however, is applicable to 'other uses, and comprises an elongated retort enveloped by concentric annular chambers in one of which steam is generated by the heat developed in the 1 retort. and in another of which air is preheated and drawn into a mixing or pressure chamber' b aspiration of the steam in the manner ofy an injector. The compressed mixture ot' air and steam in the pressure 5 chamber passes through a Venturi nozzle to carburize the fuel and to draw the fuel to the carbureter. A positive igniter is provided at the carbureter or in the retort to initially ignite the mixture to combustion in the retort, from which it emerges through a constricted nozzle as .an intense white flame. The steam and air envelopes surrounding the retort absorb radiated heat whereby they insulate and cool its walls and thus prolong its use.

A further object of this invention is to provide an automatically controlled liquid fuel combustion system in which temperature changes control the steam supply and consequently the air and fuel supply, whereby the heating effect is also controlled, and in which the retort temperature controls the ignition of the combustible.

Other objects and advantages of this i invention will become apparent from the description of a preferred embodiment thereof presented in the following specification and illustrated bv the accompanying drawings, in which like reference characters designate like parts in the several views. In the drawin Figure 1 is a longitudinal section through a' preferred apparatus embodying this invention;

Fig. 2 is a cross-sectional view of the ppaxl'atus. taken along the line 2 2 of Fig. 3 is an enlarged view, partially in section, of the water shut-off valve as seen along the line 3 3 of Fig. 2; and

Fig. 4 is a schematic diagram of a preferred electrical operating system for the controlof the apparatus.

Referring to Fig. 1, numeral l designates the elongated flame retort of the a paratus,

which is preferably disposed horizontally, but which will operate equally well in any other position desired. The end of retort 1 is provided with a constricted nozzle 2, preferably integral with an annular sleeve 3 concentric with retort 1, so as to form the steam generating chamber 4. The upper surface of sleeve 3 is pierced with jet holes 5, which enter steam chamber 4 from water chamber 6, which is covered by a plate 7 so as to be watertight. As shown particularly in Fig. 2, the lower part of steam chamber 4 is enlarged to form a Water reservoir 8, underneath which is disposed an electrical heating unit 9, which is separated from reservoir 8 by a thin metal Wall, and is encasedv by a bottom cover plate 10, from which heating unit 9 is insulated by a layer of thermal non-conducting material. so that the entire heating effect is transmitted to reservoir 8.` Sleeve 3 is threaded at 'one end and carries an adjustable collar 11, which coacts with the outside of retort 1 to form a steam nozzle 12. The outside of retort 1 at this point is formed with an inclined surface, as shown in Fig. 1, so that by turning collar 11 upon the threaded portion of sleeve 1 an adjustment in the size of steam nozzle 12 may be effected. The inner surfaces of nozzle 12 may be provided with spiral grooves so as to impart a spiral flow to the einer ing steam, if desired.

The outer sur ace of collar 11 is curved as shown in Fig. l, so that it cooperates with telescoping annular nozzles 13, 14l and 15,

-to form a multiple steam injector, which draws air into Venturitube 16, the end of which is provided with a orlobe 17 forming a mixing and expansion chamber 18. The

pressure and velocity of the air and steam mixture emerging from chamber 18 may be controlled by a throttle plate 19, which is mounted u n the inner end of shaft 20 threaded t rough globe 17 and provided with a turning handle 21. Nozzles 13, 14 and 15 are joined together by a threaded rod 22 journalled in the flange of tube 16, the successive nozzles being provided with screw threads of increasing pitch so that by turning rod 22 the spacing between the nozzles may be increased or decreased to vary the injector etl'ect at will. The outer surface of retort 1 may be tapered at this point as at nozzle 12, so that a steam velocity adjustment of nozzles 13, 14 and 15 may be obtained commensurate with the air volume adjustment effected by turning rod 22. The inner end of retort l is fitted with carburetor venturi 23, the inner end of which is shaped to form a thin shell, and into the throat of which projects the liquid fuel nozzle 24, which is preferably supplied by a pair ot small tubes 25. Into or at the emergence end of Venturi tube 23 is disposed an electrical igniter 26 which is preferably of the positive incandescent type for purposes of safet inasmuch as the sparking type readily ouls and frequently fails to ignite, which results in the' dangerous accumulation of combustible ases. Obviously can bureter 23 may be a apted to gaseous fuel as Well as to liquid fuel.

Enveloping sleeve 3 and the injector unit 13-14-15 is a jacket 27 forming air tube 28, the intake end of which is provided with a plurality louvres 27a. Jacket 27 extends beyond the injector to form an air insulating chamber, 29, in which a partial circulation is effected, since it is connected with air tube 27 by means of apertures 3() provided in the flange of Venturi tube 16. The top of jacket 27 is preferably provided with a hinged cover 31, whereby access may be had to steam nozzle adjusting collar l1, injector adjusting screw 22, and igniter 26. The electrical junction box 32 is mounted upon jacket 27, into which the electrical supply line 33 passes, and which is provided with starting and stopping switch buttons 34.

As shown in Fig. 2, the side of sleeve is provided with a chamber 35, the inner wall of which is preferably of some good thermal conductor engaging the outside surface of retort 1, and upon which is mounted a thermostatic switch 36, such as the bimetallic loop illustrated in Fig. 2.

Connected to steam chamber 8 by means of a plpe 37 is a corrugated flexible metal bellows 38 mounted in a chamber 39, which is connected to Water chamber 6 by means of supply pipe 40. Communicating with chamber 39 is another chamber 41, which is supplied by water pi pc 42. 'Mounted upon bellows 38 and controlling the opening between chambers 39 and 41 is a'double cone valve 43, which is actuated to disconnect chambers 39 and 41 by the expansion or contraction of steam actuated bellows 38 in a manner hereinafter described.

Connected to water reservoir 8 by means of pipe 44 is a chamber 44, in which moves tloat 45 according to the water level therein, so as to actuate lever 46 and rod 47, the latter passing through the core 48u of solenoid`48 which controls weighted valve 49 disposed in chamber 50 to which pipe 42 is connected. Communicating with chamber 50 is another chamber 51, which is supplied by Water pipe 52 and into which rod 47 rejects, having valve 53 at its lower en Valve 53 is pierced with small holes 54 so that when it is closed a little water may flow through into chamber 50. Likewise the Wall between chambers 50 and 51 is pierced with similar holes 55 which valve 53 normally closes, but which are open when valve 49 is closed and valve 53 is open. Vvlhen both valves 49 and 53 are closed, both groups of holes 54 and 55 are closed, since valve 53 closes holes 55 and valve 49 closes holes 54. Float valve lever 46 is preferably protected by a cover 56.

A preferred electrical control system is shown in Fig. 4, which is particularly adapted for commercial or domestic heating. The circuit comprises an external thermostatic switch 57 which is responsive to room, furnace, or other remote temperatures to open or close the circuit supplied by electrical source 53. The starting and stopping switch for the burner is designated 34, the igniter 26, the electrical heater 9, the burner thermostatic switch 36, and the shut-off valve solenoid 48. A shunt wire 62 is placed between the battery 58 and solenoid 48, and the igniter 26, heater 9 and switch 36, and contains a resistance 63 which is greater than the combined resistance of igniter 26 and heater 9 so as not to atl'cct the operation of the latter when thermostatic switch 36 is closed, and which does not a'ect the operation of solenoid 48 whether thermostatic switch 36 is open or closed. By means of wire 62 the remainder of the electrical circuit is maintained after thermostatic switch 36 opens. Obviously other connections procurinrr equivalent operation may be employer. Such an electrical scheme is inherently safe, inasmuch as neither the igniter 26 nor the heater 9 can operate if the other is inoperative, because the circuit of each traverses the other, and consequently no steam is generated to produce combustible gas if the ignitcr 26 should fail. Furthermore, When the flow of steam stops the flow of fuel stops, and thus no dangerous accumulation of fuel or fuel gas can occur. In localities where commercial electric service is unobtainable, electrical heater 9 may be lon lli

replaced by a pilot-lighted oil or (gas heater, preferably electrically controlla and 58 may be a storage battery, For use in a horizontal position, such as for domestic heating, the burner may be supplied with an adjustable tripod support comprising front leg 59 and two rear legs 60 and 61, which are preferably mounted as illustraed in Fig. 1.

Assuming a typical practical application for the purpose of describing the operation of the system, it is supposed that the apparatas has been adapted to domestic heating. When the burner is inoperative; water, at ordinary water main pressure, flows from pipe 52 into chamber 51, valve 53 being open,

through holes 55, valve 49 being closed, through pipe 42 into chamber 41, past open valve 43 into chamber 39, through pipe 40 into chamber 6, and through jets to fall upon the fluted or spiralled outer surface of retort 1 Where some of it is retained, while the remainder iows into water reservoir 8. As the water rises in reservoir 8, iioat rises until valve 53 closes and stops the flow of water through holes 55. Thus, when the burner .is in inoperative condition, water reservoir 8 is filled and the water supply is shut oil by float-controlled valve 53, and burner thermostatic switch 36 is also closed.

Assuming external thermostatic switch 5i. to be closed when switch 34 'is manually closed to start the burner into operation, solenoid 48 becomes energized and raises weighted valve 49 to permit the supply of water when needed, and igniter 26 and heater 9 become energized. Heater 9 causes the water in reservoir 8 to boil, and the resultant steam passes through nozzle 12 and into injector 13-14--15, which draws air through air tube 28 fromlouvres 2?,Pthe mixture of steam and air passing through venlturi 16 with increasing velocity and ex anding into pressure chamber 18 from which it emerges with a velocity controlled by throttle plate 19 and flows into carbureter 23. The' effective areas of tubes 16 and 23 are chosen at a ratio such that there is no back-pressure into tube 16, and so that the air and steam mixture passes through the throat of Venturi tube 23 with a very high velocity, whereby the liquid fuel in nozzle 24 is atomized, being initially supplied thereto by any well-known means such as a constant level apparatus, gravity or the capillarity of tubes 25, and thereafter drawn from nozzle 24 by aspiration when the air and steam mixture attains snicient velocit The carbureted mixture is then ignited y incandescent igniter 26, the flame propagating the entire length of retort 1 and emerging from nozzle 2. In the mean time, the steaming of the water in reservoir 8 has lowered the water level so that float 45 gradually opens valve 53 permitting a greater quantity of water to flow into chamber 51 through pipe 42 into chambers 39 and 41, ast valve 43, through pipe 4Q into water c amber 6, fromwhich 1t is sprayed through jets 5 u on the flted up e1 surface of retort 1 whic by this time, ias become suiliciently lieated by the flame therein to vaporize'the water flowing over it.

When the retort has attained a certain predetermined temperature, the thermostatic .switch 36, which is responsive to Ichanges in retort temperatures, operates to break the electrical circuit through electrical heater 9 and igniter 26, which are no longer needed, since the retort 1 furnishes the steam generating heat and the flaming interior of retort 1 maintains the ignition. This phase of the operation cycle is illustrated by Fig. 4, which shows the normal condition of the electrical circuit when the burner is in full operation. The considerable heat radiation of steam generator sleeve 3 and retort 1 is absorbed by the air drawn through louvres 2T and air tube 28 by the suction developed by steam injector 13-14-15, at which point the air is further heated to a high temperature as it mixes with the dry steam blowing over the outer lsurface of hot retort 1 before it enters Venturi tube 16 to eX and into pressure chamber 18 which steadies the iiow ast throttling plate 19 into carhureter 23.

n full operation the thin fin of carbureter 23 becomes virtually incandescent, so that the fuel from nozzle 24 is not only initially atomized by the velocity of the air and steam mixture but is subsequently completely vaporized by the heat emitted by the carbureter lin before ignition, so that complete combustion results inside of the retort 1, which is aided by the water vapor present and the preheating of the air.

It is a parent that the heat and pressure develope by the steam in generator 4 governs the heat developed by the burner, since the flowing steam induces the air of combustion, and the volume of liquid fuel used depends upon the velocity of the steam and air mixture. Accordingly, it is necessary to control the steam, since if too much steam is developed, too much heat is produced, and vice versa. Therefore, the water supply is preferably controlled by the steam by means of a flexible bellows 38, the interior of which is connected to steam generator 4 by pipe 37, as shown`in Fig. 2. Bellows 38 acts as a combined thermostat and pressure regulator, since it is responsive to temperature changes by a degree of expansion or contraction dependent upon the differential temperatures between the steam within it and of the feed water outside of it, and also acts as a pressure regulator since it responds to the variation in the steam pressure within it. Thus its operation is jointly dependent upon temperature and pressure. Assuming that excessive heat is developed suddenly when a gradual heat is required, then bellows lua Ilo

. above-described operation.

3S will expand under combined higher steam pressure and steam temperature to cause the lower cone of valve 43 to decrease the water flowing into chamber 6until normal flaming in the retort is attained and consequently normal steam ressure and steam temperature as well W ereu on valve 43 will be re-opened. n the ot er hand, assuming that the flaming in the burner is insuicient, and that too much water is being supplied to permit the recovery of the heat balance. Then the pressure of the water surrounding bellows 38 will cause the upper cone of valve 43 to decrease the water supply, there being insuilicient steam pressure within bellows 38 to counteract the outside water pressure, When the heat balance is recovered the normal steam pressure reopens valve 43 and water again llows.

When the required predetermined out.

side temperature has been attained at which thermgstatic switch 5T has been adjusted, it will open and break the electrical circuit, whereby solenoid 48 is dccnergized and releases weighted valve 49 to shut oifthe water supply, exce t for that which flows through ho es 55 to ll water reservoir 8, whereupon float 45 closes valve 53 and consequently holes 55 as well. Inasmuch as the water supply has been shut olf, steam generation ceases and with it the flaming of the retort. As the walls of retort 1 cool, thermostatic switch 36 closes the circuit through igniter 26 and heater 9, thereby placing the burner in readiness for future operation which depends upon the re-closing of outside thermostatic switch 57 in order to repeat the Switch 57 may be of the well-known thermostatic ty e, of the time-controlled ty e, or a com ined time-controlled and t ermostatic switch. Switch 34 is opened when it is desired to permanently stop the operation of the burner.

Thus a complete li uid fuel combustion system is provided w ich is safe, simple, fully automatic, silent and economical in operation, and which has no moving parts. It is to be understood, however, that this Specification describes and the accompanying rawings illustrate merely a preferred embodiment of this invention, and that changes may be freely made in form and dctail, without departing from the spirit of this invention within the scope of the appended claims. t

lat is claimed is:

l. In a h dro-carbon fuel burner, the combination o a flame chamber, a steam nerator adapted to be heated b said ame chamber, a fuel carbureter discharging into said flame chamber, a steam-o erated air suction means encircling said c vamber and dischar 'ng into said carbureter, and means dispose in said chamber `for igniting the resultant combustible. v

2. In a hydro-carbon fuel burner, the combination of a llame retort, a steam generator adapted to be heated by said retort, a steam injector connected to said generator for aspirating air, an expansion chamber receivingr onl air and steam from said injector, a fuel car ureter connected to said last named chamber and discharging into said retort, and means for igniting the carburized fuel in said retort.

3. In a hydro-carbon fuel burner, the combination of a flame retort, a steam generator adapted to be heated by said retort, an `injector for aspirating air, a nozzle for said gcneratorvdischarging steam into said injector, an ex ansion chamber into which said injector ischarges only air and steam, a. carbureter interposed between said chamber and said retort, and means for initially igniting the carburized fuel in said retort.

4. In a h dro-carbon fuel burner, the combination o a llame chamber, a steam fenerator normally heated b said chamlber, separate means for initia ly heating said generator, a steam injector connected to said steam chamber and embracing said flame chamber, a fuel carbureter operated by said injector and discharging into said llame chamber, and means disposed at the discharge end of said carbureter for initially ignitmg the carburized fuel.

5. In liquid fuel combustion system, the combination of a llame chamber, a steam generator heated thereby, a steam-operated air pump embracing said chamber, a fuel carburetor operated by said air pump and discharging into said flame chamber, means for intially igniting the combustible in said chamber, and steam-operated means for controlling the water supplied to said generator.

6. In liquid fuel combustion system, the combination of ya flame chamber, a steam generator heated thereby, a steam-operated air pump embracing said chamber, a fuel carbureter operated by said air )ump and dischar ing into said flame cham r, means for initially igniting the combustible in said chamber, and water-level operated means for controlling the water supplied to said generator.

7. In liquid fuel combustion system, the combination of a llame chamber, a steam generator heated thereby, a steam operated air pump embracing said chamber, a fuel carbureter o erated by said air pump and discharging mto said llame chamber, means for initially igniting the combustible in said chamber,I steam-operated means for controllin the water supplied to said generator, an water-level operated means for controlling the water supplied to said steam-operated means.

8. In liquid fuel combustion system the combination of a llame chamber, a steam generator heated thereby, a steam operated f air punp embracing said chamber, a fuel carbureter operated by said 'air pump and discharging into said flame chamber, means for initially igniting the combustible in said chamber, and external temperature responsive means for controlling said igniting means.

9. In liquid fuel combustion system, the combination of a flame chamber, a steam generator heated thereby, a steam operated air pump embracing said chamber, a fuel carbureter operated by said air i ump and discharging into said flame cham er, means for initially igniting thc combustible in said chamber, and thermostaticmeans res onsive to the temperature of said llame c amber for controlling said igniting means.

10. In liquid fuel combustion system, the combination of a flame chamber, a steam' generator heated thereby, a steam-operated air pnmp embracing said chamber, a fuel carbureter operated b said air pump and discharging into said urne chambers, means for initially igniting the combustible in said chamber, primar external thermostatic means for contro ing said igniting means, and secondary thermostatic means responsive to the tem erature in said chamber for controlling sai igniting means.

11. In a liquid fuel combustion s stem, the combination of a flame cham er, a steam enerator normally heated by said flame c amber, an injector embracing said chamber, means for initially heating said generator, a fuel carbureter disposed between said injector and said chamber, means for initially igniting the combustible in said chamber, and external thermostatic means for controlling said heating and igniting means.

12. In a liquid fuel combustion system, the combination of aflame chamber, a steam generator normally heated by said flame chamber, an injector embracing said chamber, means for initially heating said generator, a fuel carbureter disposed between said injector and said chamber, means for initially igniting the combustible in said chamber, and thermostatic means responsive to the temperature in said chamber for controlllng said heating and igniting means.

13. In a liquld fuel combustion system, the combination of a flame chamber, a steam generatior normally heated by said flame chamber, an injector embracing said chamber, means for initially heating said generator, a fuel carbureter disposed between said injector and said chamber, means for mitially igniting the combustible in said chamber, primar external thermostatic means for controlling said heatin and igniting means, and secondary t ermostatic means responsive to the tem erature in said chamber for controlling said heating and igniting means.

14. In a liquid fuel burner utilizing steam, the combination of a steam generator, a' water-level controlled water supply valve connected to said generator, a separate steamcontrolled water supply valve connected to said first-named valve and said generator, and a water shut-0E valve cooperating with said first-named valve.

15. In a liquid fuel burner utilizing steam a. flame chamber, a steam generator4 heated by said chamber, a water supply valve for said generator, means responsive to the Water level in said generator for controlling said vafve, and a steam-controlled valve connected to said generator and to said firstnamed valve for controlling. the water supplied by said first-named valve.

16. In a hydro-carbon fuel burner, the combination of a source of steam, an injector operated by the steam for aspirating air, a ame chamber within the injector, a fuel carbureter discharging into said flame chamber and operated b said injector, and ignition means in said ame chamber.

17. In a hydro-carbon fuel burner, the combination of a source of steam, an injector operated by the steam for aspirating air, a flame chamber within the injector, a fuel carbureter discharging into said flame chamber and operated by said injector, a throttling means disposed between said injector and said carburetor, and ignition means in said flame chamber.

18., The method of hydro-carbon fuel combustion, which consists in inducing an air draft by a steam jet, expanding the mixture, increasmg the velocit of the flowing mixture by throttling, utilizin the mixture at said velocity to atomize t e fuel, igniting the resultant combustible, and `controlling the steam supply `in accordance with the temperature and pressure thereof.

19. The method of hydro-carbon fuel combustion, which consists in inducingr an air draft by a steam jet expanding the resultant mixture of air and steam, increasing the velocity of the flowing mixture by throttling, utilizing the mixture at said velocity to atomize the fuel, igniting the resultant combustible, and controlling the ignition by means of the flame temperatures.

20. The method of hydro-carbon fuel combustion, which consists in aspirating air for combustion by means of flowing steam` expanding the mixture, contracting the mixture to increase the velocity thereof, Vaporizing the fuel by the heated mixture at that velocity, igniting the resultant combustible, and controllingI the steam in roportion to the heat and pressure thereof.)

21. The method of hydro-carbon fuel combustion, which consists in initially generating steam b separate heating, aspirating air by means o the flowing steam` reversin the flow of the mixture, vaporizing the fue 23. In a hydro-carbon fuel burner the combination of an elongated retort, a steam generator enveloping a portion of the retort, steam-operated air suction means enveloping another portion of the retort and communicating with the generator, means for conducting the air into one end of the retort, a fuel carburetor in the retort, and an opening at the other end of the retort.

In testimony whereof I affix m signature.

WALTER FREE.

CERTIFICATE or comcT1oN-` Patent No. 1,689, 667.

vGranted October 30, 1928, to

Imran u. FREE.

lt ia hereby certified that' error appears in the abore numbered patent .requiring correction as follows: In the drawings Figure 4. the Horizontal line appearing next below the horizontal line 62 should he canceled; and tbat the said Letters Patent almld be `reatl with this correction therein that thesame may conform to the record of tbe cale in tbe Patent Office.

Signed and sealed this 15th day of January, A. D. 1929.

(sul) M. J. Moore. Act-ing Commissioner of Patents.

23. In a hydro-carbon fuel burner the combination of an elongated retort, a steam generator enveloping a portion of the retort, steam-operated air suction means enveloping another portion of the retort and communicating with the generator, means for conducting the air into one end of the retort, a fuel carburetor in the retort, and an opening at the other end of the retort.

In testimony whereof I affix m signature.

WALTER FREE.

CERTIFICATE or comcT1oN-` Patent No. 1,689, 667.

vGranted October 30, 1928, to

Imran u. FREE.

lt ia hereby certified that' error appears in the abore numbered patent .requiring correction as follows: In the drawings Figure 4. the Horizontal line appearing next below the horizontal line 62 should he canceled; and tbat the said Letters Patent almld be `reatl with this correction therein that thesame may conform to the record of tbe cale in tbe Patent Office.

Signed and sealed this 15th day of January, A. D. 1929.

(sul) M. J. Moore. Act-ing Commissioner of Patents. 

